Rear Disc Brake Conversion '73 J4000 Dana 60-2

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Kowpie
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Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by Kowpie »

Greetings
I have been meaning to write of my experiences of upgrading the brakes while doing a body-off restoration of my 1973 J4000. My reasoning is to possibly help others who may contemplate this conversion in the future. As a bit of background, personally, I am a proponent of restoring these vehicles back to their original glory. With that being said, I am not a purist. I find some modern safety features are a plus, especially if the vehicle is to be used frequently, as this one will be for pulling a vintage travel trailer. I have done both the front and rear conversions to disc. The rear is the Dana 60-2 and the front is the closed knuckle Dana 44. The rear is the subject of this post. The older style axles and the "outboard" springs intrigue me. The aesthetics hearken back to a more basic and simpler time and this is why have decided to keep them. I will probably do several posts as one, all encompassing post might bore the heck out of most.
The parts list:

1) Rear Disc Conversion, #2580J20PB.
The kit was purchased from TSM MFG. Co., Inc. out of Castle Rock, Colorado. I paid around $750.00 (Spring of 2022) for the kit but I see it now sells for $921.00 www.tsmmfg.net/jeep-j20-complete-rear-d ... 80j20.html
David was amazing to deal with and prompt with his replies. I will say that I asked several questions and he was always gracious and helpful. The kit is full of well made items and complete but there were some negatives to report. The kit comes with a spacer (measures 0.117" thick), which is used to take up the space that the backing plate (measures 0.187" thick) would normally reside, it was too thin. I spoke with David, and he said in 25 years of selling the kit he had not encountered this anomaly but was able to send a Ford style spacer at 0.178" thick. After purchasing 0.010" shim stock I was able to use this spacer. This spacing is critical since it applies the correct pressure to the outer axle seal that in turn retains the axle bearing. Another issue I had was the spacers provided to allow the caliper to be centered on the rotor did not allow for proper clearance. The bracket that mounts the caliper to the axle bearing retainer/main mount had to be modified. An finally, the I.D. of the outer bearing retainer/ caliper mount had to be opened up to clear the lips of the outer seal. Had this retainer I.D. been left as-is, it would have crushed the outer rubber lips leading to premature failure down the road. The kit was good quality, customer service from TSM was top-notch, and the kit was comprehensive to the point of including new stainless braided flex hoses with weld-on axle tabs. Now maybe my issues with kit fitment were that I have an odd Dana 60-2 or possibly it had been modified over the last 50ish years, I do not know but in my experience, extensive modifications had to be made. It could have been worse had TSM not stood behind their product.

2) Rear Axle Bearing, Retainer, Outer Seal, Inner Seal
When installing the above conversion kit, the axle bearings and seal must be changed due to the caliper mount/outer bearing retainer captured between the bearing and the axle flange. My search for these components was exhaustive but productive. I will exaggerate and say that NOBODY lists these parts by application anymore. Hopefully, my experiences here will help. The parts are readily available. KEEP THESE PART NUMBERS HANDY!!!
Rear Axle Bearing, Spicer #565904, purchased from RockAuto $57.79
Rear Axle Bearing Retainer, Spicer #35961, RockAuto $7.30
Rear Axle Inner Seal, Spicer #35512, RockAuto $3.91
Rear Axle Outer Seal, CR Seals, #21244, Purchased from CR on Ebay $22.91

Cheers!
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Last edited by Kowpie on Mon Sep 26, 2022 1:47 pm, edited 1 time in total.
'65 Wagoneer, 230 OHC, IFS, Column Shift T90/D20
'73 J4000, 6000#, 258, T18/D20, 33", full disc.
'79 CJ7, 304, T18/D20, 35", 4.56, SOA, shackle reversal.
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Kowpie
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Re: Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by Kowpie »

More pictures
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'65 Wagoneer, 230 OHC, IFS, Column Shift T90/D20
'73 J4000, 6000#, 258, T18/D20, 33", full disc.
'79 CJ7, 304, T18/D20, 35", 4.56, SOA, shackle reversal.
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Topic author
Kowpie
Posts: 155
Joined: Wed Jun 10, 2020 3:41 pm
Location: Southern Oregon

Re: Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by Kowpie »

And finally...
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'65 Wagoneer, 230 OHC, IFS, Column Shift T90/D20
'73 J4000, 6000#, 258, T18/D20, 33", full disc.
'79 CJ7, 304, T18/D20, 35", 4.56, SOA, shackle reversal.
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Stuka
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Re: Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by Stuka »

Some really great info in this thread, thanks for posting it up!
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
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tgreese
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Re: Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by tgreese »

Interesting. Good work. What did TSM say about using their kit on a 60-2? Most of the D60 rear axles out there are full-floating which Jeep calls a Dana 60-3. I would not assume that the kit for a generic "Dana 60" would fit here.

The 60-2 used in some of our trucks is a "semi-full-floating" axle with a single outboard bearing and a flanged axle shaft like a Dana 44. It was used in the middle GVWR ratings, a so-called "heavy half-ton" rating. It replaced the Dana 53 used in earlier years, that came with tapered axles. These 60-2 axles were popular for conversion in other Jeeps, ie CJs, when narrowed to the needed track width. With a 5-on-5.5" bolt pattern, they matched the smaller Jeep's lug pattern while providing most of the 60's strength. I wonder what they did for brakes.

Even a decade or two ago, the 12"x2" brake drums for these axles were all gone. No NOS, no good used, nothing. This leaves owners in a spot - what to do about the rear axle when their drums are worn out? Front disc brake conversion for these trucks is the same as any of the Jeeps with closed-knuckle front axles, but what to do about the rear? I wonder if you could convert the rears to 11"x2" Jeep drum brakes, and convert the fronts to disc. Kinda think the braking would be fine with front discs and the smaller rear drums.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
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Kowpie
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Re: Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by Kowpie »

Stuka wrote: Tue Sep 27, 2022 6:33 am Some really great info in this thread, thanks for posting it up!
Thanks Stuka, this was the least that I could do. I have gleaned so much information from people who took the time to post here that it was time to give back some. I am a bit of a technological peasant so sometimes doing this is a stretch. So this is my "thanks" to all those who have shared and continue to do so.
'65 Wagoneer, 230 OHC, IFS, Column Shift T90/D20
'73 J4000, 6000#, 258, T18/D20, 33", full disc.
'79 CJ7, 304, T18/D20, 35", 4.56, SOA, shackle reversal.
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Stuka
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Re: Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by Stuka »

tgreese wrote: Tue Sep 27, 2022 8:25 am Interesting. Good work. What did TSM say about using their kit on a 60-2? Most of the D60 rear axles out there are full-floating which Jeep calls a Dana 60-3. I would not assume that the kit for a generic "Dana 60" would fit here.

The 60-2 used in some of our trucks is a "semi-full-floating" axle with a single outboard bearing and a flanged axle shaft like a Dana 44. It was used in the middle GVWR ratings, a so-called "heavy half-ton" rating. It replaced the Dana 53 used in earlier years, that came with tapered axles. These 60-2 axles were popular for conversion in other Jeeps, ie CJs, when narrowed to the needed track width. With a 5-on-5.5" bolt pattern, they matched the smaller Jeep's lug pattern while providing most of the 60's strength. I wonder what they did for brakes.

Even a decade or two ago, the 12"x2" brake drums for these axles were all gone. No NOS, no good used, nothing. This leaves owners in a spot - what to do about the rear axle when their drums are worn out? Front disc brake conversion for these trucks is the same as any of the Jeeps with closed-knuckle front axles, but what to do about the rear? I wonder if you could convert the rears to 11"x2" Jeep drum brakes, and convert the fronts to disc. Kinda think the braking would be fine with front discs and the smaller rear drums.
D60-2 axles were still being manufactured up through the 2000's for ford econoline vans. Though these used different brakes, and they were quite wide. And as I recall, they kept the old 8x6.5 lug pattern. As fleets didnt want a mix of 8x6.5 and metric 8 lug patterns to make tire/wheel switch outs easier.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
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Topic author
Kowpie
Posts: 155
Joined: Wed Jun 10, 2020 3:41 pm
Location: Southern Oregon

Re: Rear Disc Brake Conversion '73 J4000 Dana 60-2

Post by Kowpie »

tgreese wrote: Tue Sep 27, 2022 8:25 am Interesting. Good work. What did TSM say about using their kit on a 60-2? Most of the D60 rear axles out there are full-floating which Jeep calls a Dana 60-3. I would not assume that the kit for a generic "Dana 60" would fit here.

The 60-2 used in some of our trucks is a "semi-full-floating" axle with a single outboard bearing and a flanged axle shaft like a Dana 44. It was used in the middle GVWR ratings, a so-called "heavy half-ton" rating. It replaced the Dana 53 used in earlier years, that came with tapered axles. These 60-2 axles were popular for conversion in other Jeeps, ie CJs, when narrowed to the needed track width. With a 5-on-5.5" bolt pattern, they matched the smaller Jeep's lug pattern while providing most of the 60's strength. I wonder what they did for brakes.

Even a decade or two ago, the 12"x2" brake drums for these axles were all gone. No NOS, no good used, nothing. This leaves owners in a spot - what to do about the rear axle when their drums are worn out? Front disc brake conversion for these trucks is the same as any of the Jeeps with closed-knuckle front axles, but what to do about the rear? I wonder if you could convert the rears to 11"x2" Jeep drum brakes, and convert the fronts to disc. Kinda think the braking would be fine with front discs and the smaller rear drums.
Thanks Tim
1) Supposedly, the kit is designed specifically for the 5x5.5 semi-float 60-2. From their listing: "Jeep 1969 - Mid 1973 J-20 Dana 60-2, 5 lugs x 5 1/2 inch Wheel Lug Pattern". Not sure why they say J20, as that identifier did not start until 1974.
2) Exactly as you stated, while searching for parts I found numerous posts from the CJ crowd using this axle as an upgrade. One of these posts did this same conversion. This is where I discovered the manufacturer TSM.
3) Once the truck is on the road and functioning properly, I will decide if I keep all of the original 12"x2" drum components or pass them on to someone in need.
4) Yes, a conversion to a more common drum brake size would be less cost prohibitive.
'65 Wagoneer, 230 OHC, IFS, Column Shift T90/D20
'73 J4000, 6000#, 258, T18/D20, 33", full disc.
'79 CJ7, 304, T18/D20, 35", 4.56, SOA, shackle reversal.
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